const gender = Symbol('grnder');
const obj = {
    name: '朱俊德',
    age: 17,
    [gender]: '男'
}
// obj.name
// console.log(obj[gender]);
// console.log(JSON.stringify(obj));
// console.log(Object.getOwnPropertySymbols(obj));

// 反射类型，语言的高级特性
console.log(Reflect.ownkeys(obj));